Sampling Results

During the last sampling cycle we have taken hundreds of water samples in order to determine the presence of any radioactive, biological, inorganic, volatile organic, or synthetic organic contaminants. The table below shows only those contaminants that were detected in the water. The state requires us to monitor for certain substances less than once per year because the concentrations of these substances do not change frequently. In these cases, the most recent sample data are included, along with the year in which the sample was taken.

1 Results in the Level Detected column for radiological contaminants and inorganic contaminants are the highest average at any of the sampling points or the highest detected level at any sampling point, depending on the sampling frequency.

2 The result in the lowest monthly percentage column is the lowest monthly percentage of samples meeting the turbidity limits reported in the Monthly Operating Report. Turbidity is a measure of the cloudiness of the water. It is monitored because it is a good indicator of the effectiveness of the filtration system. During the reporting year, 100% of all samples taken to measure turbidity met water quality standards.

3 The result in the Level Detected column is the annual average of the quarterly averages and the Range of Results is the range of results (lowest to highest) at the individual sampling sites.

4 The result in the Level Detected column are the highest of the four quarterly running annual averages of results from all sampling sites.

5 The result in the Level Detected column for TOC is the lowest of the four quarterly running annual averages ratio of results from all sampling sites. Total organic carbon has no health effects. However, total organic carbon provides a medium for the formation of disinfection by-products. These by-products include trihalomethanes (THMs) and haloacetic acids (HAAs). Drinking water that contains these by-products in excess of the MCL may lead to adverse health effects; liver or kidney problems; nervous system effects; and may lead to an increased risk of getting cancer.

Table Definitions

AL (Action Level): The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.

MCL (Maximum Contaminant Level): The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.

MCLG (Maximum Contaminant Level Goal): The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.

MRDL (Maximum Residual Disinfectant Level): The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

MRDLG (Maximum Residual Disinfectant Level Goal): The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contamination.

NA:Not applicable

ND: Not detected and indicates that the substance was not found by laboratory analysis.

NTU (Nephelometric Turbidity Units): Measurement of the clarity, or turbidity, of water.

pCi/L (picocuries per liter): A measure of radioactivity.

ppb (parts per billion): One part substance per billion parts water (or micrograms per liter).

PPM (parts per million): One part substance per million parts water (or milligrams per liter).

removal ratio: The monthly removal ratio is the ratio between the actual TOC removal and the TOC rule removal requirements.

TT (Treatment Technique): A required process intended to reduce the level of a contaminant in drinking water.